In recent years, flash-based storage gradually replaces traditional hard disks to be storage of consumer electronics. Compared to hard disks, flash-based storage has some advantages, such as better performance, lower energy consumption, shock resistance, and compact size.
However, flash-based storage differs from hard disk in characteristic of out-of-place update, which the page cannot be re-written before erase operation in flash technology. When a user would like to update data which has written into a page of the flash-based storage, the user needs to write the updated data to a new blank page and the logical address is re-mapped to the new page to complete the data update.
In other words, when the written data needs to be updated, a new copy of the data is written (programmed) into a new blank page, and the logical address is re-mapped to this new page. Due to the aforementioned, one or more copies are generated and left in the flash-based storage after updating data.
The flash-based storage cannot directly erase the pages having those copies. Hackers could use those copies to rebuild data, and this is a hidden risk of data security. In addition, a method of erasing memory blocks after garbage collection would degrade the performance of the flash-based storage and shorten the lifetime of the flash-based storage. Therefore, there is a need to provide a data management method for a memory and a memory apparatus to remove data copies when the user updates a data.